Let's say you just want to see your 10 x 20 Tent in your inventory. You can search "10 X 20 Tent" and your inventory will pull up that specific item.
Next, let's say you want to see just your tents and sidewalls. You can enter Tent OR Sidewall to see all of your tents, along with all of your sidewalls.
Finally, let's imagine you want to look in your inventory for all your 10 foot tents and any other piece that goes along with them. You can enter Tent AND 10 to quickly show you all your items that contain both the words 'Tent' and '10'.